Another one! Why can't we say this stain remover is very efficient. Why do we say effective? What is the difference?

Question

What are facilities and what amenities?
When do we use specimen and when sample?

Answer 1

I'll post how I use those words:

I use "efficient" when I refer to people who do their jobs well and without wasting time.

I use "effective" when I refer to things or concepts.

I use "facilities" when I refer to buildings, building complexes, or parts of buildings.

I use "amenities" when I refer to a feature or quality that provides good things, benefits. http://www.answers.com/topic/amenity

I'll leave the last two to a person who works/has worked in science.

Answer 2

Sample means something representing the whole. A sample of cake, a sample of soil: Sample means some portion meant to represent the entirity.
Specimen: It does not imply the whole is like the specimen. In fact, specimens are uaually intended to display some variance with the norm. His specimen indicated usage of illegal drugs during this time.